Break in Louhi Service

Operating System Update

The operating system of the compute nodes of Louhi will be updated from
Catamount to Cray Linux Environment (CLE), formerly known as Compute
Node Linux (CNL), in February 4-5.

Due to the OS update all the compute node programs have to be recompiled and relinked. See below for more information.

Memory Upgrade

At the same time the memory of 576 compute cores will be upgraded from 1 GB to 2 GB. CLE facilitates the utilization of the inhomogeneous memory and is also required by the quad core processors that will be installed later on.

Porting Programs to CLE

To make the transition easier CSC will allow limited use of Cray XT3 Tahko, an internal test system, for CLE testing before the Louhi OS update. Tahko has 52 single core Opteron nodes and the latest CLE operating system.

Only short test runs are permitted so that everybody gets a chance to test his or her code in  a reasonable time. Production runs are strictly prohibited. CSC does not guarantee the stability of the system, there can be breaks without a prior notice.

• If you need a porting/testing account on Tahko, please send a message with contact information to usermgr at csc.fi
• The Tahko porting/testing period will start on Mon, January 21
• If you need help in porting your code or encounter any problems with Tahko or CLE, contact Jussi Heikonen (jussi.heikonen at csc.fi)
  

Further information

• Tahko Quick Reference
  
• See also the updated Louhi User's Guide (under construction)
• Jussi Heikonen (jussi.heikonen at csc.fi), tel. 457 2065